Objectives The aim of this study was to evaluate the relationship between cholesterol metabolism and coronary plaque vulnerability. Background Cholesterol homeostasis, defined as the balance between absorption and synthesis, influences the progression of coronary atherosclerosis. Methods Consecutive stable angina pectoris patients (N = 80) not receiving any lipid-lowering therapy were divided into 2 groups based on the presence of in vivo thin cap fibroatheroma (TCFA) in de novo target vessels assessed by the combined use of virtual histology intravascular ultrasound and optical coherence tomography. Results Patients with in vivo TCFA (n = 42) showed a higher campesterol-to-lathosterol ratio (3.36 [interquartile range ...